Optoelectronic component

ABSTRACT

Provided are optoelectronic components which include an optoelectronic device mounted on a silicon substrate and a flexible circuit electrically connected to the optoelectronic device.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 11/124,775,filed May 9, 2005, which is a continuation-in-part of application Ser.No. 10/192,752, filed Jul. 10, 2002, which is a continuation ofapplication Ser. No. 09/574,482, filed May 19, 2000, now abandoned,which is a continuation-in-part of application Ser. No. 09/199,545,filed Nov. 25, 1998, now abandoned. The contents of each of theseapplications are incorporated herein by reference.

BACKGROUND OF THE INVENTION

To date designs and methods of manufacturing photonics transmit/receivemodules have relied on complicated techniques of aligning the lightemitting and detecting elements, of encapsulating said elements, and ofcombining the carrier with an optical connector. This is especially trueof arrays combining one or more light emitting or detecting devices inparallel. Attempts at handling Vertical Cavity Surface Emitting Lasersor VCSELs and their arrays, as well as photodetectors and their arraysfor use in fiber Tx, Rx and Tx/Rx packages have often involved changingthe optical axis of the chips—allowing them to interface with v-groovesin a silicon substrate such as in U.S. Pat. No. 5,337,391. Other groupshave employed methods to change the optical axis that employ the use ofangle polished fiber or flexible waveguide arrays such as HewlettPackard's Parallel Optical Link Organization (POLO) [Hahn, K. H. PLOL“Parallel optical links for gigabyte data communications”, in theProceedings of the 45th Electronics Components and Technology ConferenceProceedings, pgs. 7-8]. Other designs have involved several complicatedparts such as U.S. Pat. No. 5,337,398, or have involved the mounting ofdevices on an optical jumper block such as U.S. Pat. No. 5,719,978 or onthe endface of a polished fiber array block such as in the MotorolaOptobus [Schwartz, D. B., C. K. Y. Chun, B. M. Foley, D. H. Hartman, M.Lebby, H. C. Lee, C. L. Sheih, S. M. Kuo, S. G. Shook, and B. Webb,1995, a low cost, high performance optical interconnect. In theProceedings of the 45th Electronics Components and TechnologyConference, pgs. 376-379. Piscataway, N.J.: IEEE]. All of thesereferences are hereby incorporated by reference herein. One priorattempt at monolithic integration using stacks of self aligned chipsutilized ball lenses between the stacks to couple optical fibers to theoptically active device as was seen in U.S. Pat. No. 5,259,054.

These earlier methods of handling optically active elements, especiallysurface emitting or receiving devices as arrays—as well as positioningof discrete components—has been very complex, expensive, and lacking insimplicity of design thus making the designs non usuable in the currentmanufacturing climate. The current invention relates to a new techniquefor creating a “face-plate” module for handling such active devices. Theinvention has wide application in making connection to existing andfuture parallel optical fiber array connectors in its ability to usemodified existing ferrules and their alignment mechanisms and accuratelyalign the optical elements of the carrier to the optical fibers.

This eliminates all need for expensive and hard to machine components,costly labor machining and complicated assembly techniques. The deviceis exceptionally useful for creating cost effective small form factortransceivers and parallel Tx/Rx modules. The invention allows a greaterdegree of monolithic integration than previously possible and eliminatesmany of the parts and steps previously required such as optical jumperblocks, polishing operations, etc. Such steps are very expensive toperform and time consuming thus adding to the price of the componentmember. The invention also will find application in chip to chip andboard to board interconnects allowing easier cost effective packaging ofthe optical elements.

New and existing technologies in micromachining of silicon and othermaterials allow a greater degree of precision to be obtained in formingcavities and holes in substrates. For example the Bosch process hasdemonstrated through—wafer etching with excellent control of dimensionsat etch rates making new mechanical structures possible. Newer deep dryetching technologies and wet anisotropic technologies—that have alreadybeen demonstrated in silicon wafers in conjunction with betterencapsulants—make manufacture of these devices possible at this time. Itis expected similar etching technologies will become available for otherceramic, glass, injection or transfer molded plastics, and othermaterials. In addition, parts of the design may find economicmanufacture in the future using molding processes, laser machining,light/laser assisted chemical machining, etc.

The devices disclosed are various embodiments of a novel carrier forutilizing one or more optically active devices or elements (here meaninglasers such as VCSELs and VCSEL arrays, photodetectors and photodetectorarrays, Light Emitting Diodes or LEDs, Super Luminescent LEDs or SLEDs,etc.) allowing them to be precisely positioned, electrically connected,encapsulated, optionally lensed, and heat sinked. The applicationsinclude chip to chip, board to board, and fiber optic and especiallyfiber optic array transmit, receive and transceiver modules. Theapproach disclosed can eliminate the need for polishing an assembly toform an optical surface, active alignment of the active optical elementsto the carrier, and/or active alignment of the carrier to a connectorassembly. Patterned metallizations and solders become incorporated inthis design using techniques such as shadow masking, lift-off, selectiveCVD metal deposition, and can be combined with plating using electrolessmethods or any of the known electroplating techniques.

SUMMARY OF THE INVENTION

The invention disclosed addresses the previously discussed problemsinherent in the prior art by providing a simple, easily manufacturable,passively aligned method of coupling an optoelectronic device to a fiberor fiber array with most steps integrated at the wafer level. Thepassive and self correcting feature of the alignment method provides foran efficient and simple component to be added onto already existingcomponents thus making its incorporation into the manufacturing processa desirable goal.

In fashioning the present invention, the preferred substrate material isa silicon wafer in which many substrate portions can be machined beforebeing diced or cleaved into many components. Other equivalent materialmay be substituted only if suitable machining technologies aredeveloped. Machining of silicon is a new art form in the manufacture ofelectronic components on a mass scale and it is precision work.

In a preferred embodiment of the invention, a substrate comprises partof the subassembly—with a precisely machined or formed trench in whichthe optoelectronic device is placed and aligned, with metallized bondpads and circuit traces to which the device can be electricallyconnected, with encapsulant filling the trench to encapsulate the deviceand provide a molded surface for later optical coupling, and withprecisely machined or formed through holes or angled edges which serveas alignment guides for alignment fixtures such as pins to come through.The substrate is then placed onto alignment pins of a fiber opticconnector housing and bonded to the housing of the connector while thepins hold the substrate in alignment. The pins may later be removed orleft in place. The bonded fiber optic connector can be machined orformed to house a back side heat sink and the electrical leads for theoptoelectronic device and possibly drivers mounted in the substrate.

In another embodiment, the trench that houses the optoelectronic devicecan be machined in the back side of the substrate, and a smaller windowcan be machined in the front of the substrate for the device to showthrough. In cases where the light to be transmitted or received is at awavelength where the substrate is transparent, the front side windowneed not be machined.

In a further embodiment, alignment trenches or grooves are machined orformed into the front or back surface of the substrate so that a fittedcylindrical or spherical object can be inserted. This mechanism allows anew substrate with the same feature (alignment trench) to be aligned tothe cylinder or sphere, thereby to also be aligned to the firstsubstrate.

In yet another embodiment, the circuit traces for the optoelectronicdevice can extend into and through (perpendicular to the surface) thesubstrate instead of lying parallel to the front or back surface. Thisallows for simple front to back side electrical connection. Themetallized via holes can also be cut in half, allowing electricalconnection access to the surface perpendicular to the surface in whichthe device is mounted. This feature becomes important when it isdesirable to affix a flexible circuit member to the subassembly alongthe edge of the substrate. This feature also allows direct bonding orsecondary substrate mounting with a solder bump connection.

In a still further embodiment, the encapsulant that encapsulates theoptoelectronic device can be shaped or altered to form lenses, gratings,mirrors, waveguides or other optical elements. This feature allows forbeam shaping and/or the redirection of the light to anotheroptoelectronic or waveguiding device. It should be noted that holes canbe machined right through the wafer or substrate for insertion ofoptical fibers adapted to transmit from one side of the wafer orsubstrate to the other.

In yet another embodiment, an optoelectronic component is provided. Theoptoelectronic component includes a substrate having a front surface, aback surface and a trench in the front surface, an optoelectronic devicein the trench, and an encapsulant contained within the trench. Theencapsulant provides an optical surface.

In yet another embodiment, an optoelectronic component is provided. Theoptoelectronic component includes a planar silicon substrate having afront surface, a back surface and a trench in the front surface, anoptoelectronic device in the trench and an encapsulant covering theoptoelectronic device. The encapsulant provides an optical surface.

In yet another embodiment, an optoelectronic component is provided. Theoptoelectronic component includes a planar substrate having a frontsurface, a back surface and a trench in the front surface, anoptoelectronic device in the trench, an encapsulant covering theoptoelectronic device, and an optical element inserted into theencapsulant for focusing or reflecting light, or for altering the lighttransmission qualities of the encapsulant.

A first object of the invention is to provide a simple means of aligninga single or arrayed surface emitting or receiving optoelectronic deviceto a single or arrayed fiber optic connector.

It is another object of the invention to provide an encapsulated trenchfor the device that eliminates the need for polishing.

It is yet another object of the invention to provide an improvedoptoelectronic module.

It is still another object of this invention to provide a innovativemethod for producing an improved optoelectronic module.

It is yet another object of this invention to provide a superioralignment guide and component for optoelectronic components utilizingguide pins and or beveled surfaces.

It is still another object to provide an improved alignment componentfor optoelectronic devices which is incorporated directly into thedevice.

Yet another object of this invention is to provide a method of makingoptoelectronic components where a large amount of steps are donefacilitating wafer level integration of the method.

Still another object of this invention it to provide an optoelectroniccomponent which provides a passively aligned platform for an activedevice yet still utilizes existing coupling components thus enhancingsaved costs.

Further objects include the use of a one time passive alignment andinsertion of an optoelectronic carrier and coupler component to anexisting assembly and the provision of a superior assembly.

Other objects of this invention include optimal connections of thecomponent to other components such as heat sinks, IC circuits and thelike.

These and other objects will become apparent and will be demonstrated inthe following drawings and text showing that the disclosed inventionoffers an easily manufacturable, passively aligned solution to aphotonics packaging problem that has only been solved previously bycomplex or costly designs.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective cut-away view of the present invention showing amale connector piece of an optoelectronic subassembly for coupling tothe arrayed device on a substrate;

FIG. 2 illustrates a machined or formed trench in a substrate forproviding alignment of an optoelectronic device;

FIGS. 3 a through 3 e illustrate various embodiments of the machined orformed trench in a substrate;

FIGS. 4 a through 4 c illustrate various embodiments of machined orformed trenches in the back surface of a substrate for theoptoelectronic device to be placed face-first within;

FIGS. 5 a through 5 q illustrate variously shaped through holes whichallow for alignment by pins or other cylindrical alignment mechanism;

FIG. 6 illustrates metallized circuit traces and bond pads on asubstrate;

FIG. 7 illustrates the addition of a solder eutectic pad and trace on asubstrate;

FIGS. 8 a, 8 e and 8 i illustrate various ways to achieve perpendicularcircuit access on the edge of a substrate, with FIGS. 8 b, 8 c and 8 drepresenting cross-sectional features of FIG. 8 a, FIGS. 8 f, 8 g and 8h representing cross-sectional features of FIG. 8 b and FIGS. 8 j, 8 kand 8 l representing cross-sectional features of FIG. 8 l, as shown;

FIG. 9 illustrates the placement of the optoelectronic device in itsalignment trench along with ball wire bonds to metallized pads on thesurface of a substrate;

FIG. 10 illustrates the use of a flexible circuit as a means to accessthe electrical circuit on a substrate, and FIGS. 14 a through 11 e showthe methods for providing metallization and, hence, electricalconnection, to the back of a substrate with the use of through holes;

FIG. 12 a illustrates the injection of a known volume and subsequentcuring of an encapsulant that comes flush to the surface of the trenchthat houses the optoelectronic device, and FIG. 12 b shows a top view ofthe substrate of FIG. 12 a;

FIG. 13 a illustrates a different embodiment of the substrate, where theoptoelectronic device alignment trench is on the back side of thesubstrate, and where the device's active area shows through an openwindow on the front side and FIGS. 13 b show a top view of the substrateof FIG. 13 a. FIGS. 13 c and 13 d show the metallization andencapsulation for the substrate of FIG. 13 a;

FIGS. 14 a and 14 b illustrate two embodiments of theencapsulation—where the encapsulant can be precisely formed to shapeoptical elements;

FIGS. 15 a through 15 c illustrate the method by which a heat sink isplaced within an optical connector housing and how the substrate anddevice subassembly can be simply aligned to the same connectorhousing—allowing coupling to the connector housing's mating opticalconnector; and

FIGS. 16 a through 16 c illustrate the alignment and connection of afiber optic array connector to a subassembly.

DETAILED DESCRIPTION

FIG. 1 illustrates a mating part of an optical connector, where theother part of the connector (not shown) is an arrayed or singlewaveguide or fiber optic connector with fibers or waveguides embeddedtherein. The connector halves are to be mated by means of the alignmentpins 60. The optoelectronic coupler subassembly 195 illustrated ispartly comprised of a substrate 29 which has in it a machined or formedtrench 23 in which an optoelectronic device 21 is placed, thatoptoelectronic device being any device which receives or emits light,and especially in, but not limited to, the direction perpendicular tothe substrate's 29 front surface. The preferred embodiment of theinvention is where the device 21 is a Vertical Cavity Surface EmittingLaser or VCSEL. The device 21 can have ball wire bonds 30 that affix tobond pads on or in the substrate. Electrically conductive traces, bondpads, and solder 24 are deposited onto the surface of the substrate toallow for simple electrical connection from a fanout circuit to theoptoelectronic device via ball wire bonds and/or “flip chip” bonding tothe traces. The electrically conductive circuits may be metal or may bediffused conductors in the substrate. The bond pads or solder bumps 25at the top or front of the pictured substrate 29 can be electricallyconnected to flex circuit, wire bonds, ball grid arrays, or any fittingelectrical connector. The trench 23 is injected with an encapsulant 162which encapsulates the device 21 and can provide a flush, optically flatsurface for coupling to the device 21 preferably without the need forpolishing. Polishing has been required in the past due to the largeamount of machining needed on the surface of the elements. Polishedsurfaces were needed to insure good face-to-face contact betweensurfaces and to provide good and complete contact for bonding. Theencapsulant can also provide focusing, reflecting, or waveguidingoptical elements to redirect light within its confines. The encapsulantcan be molded or chemically altered to produce this effect, or aseparate optical element can be embedded within its confines. The holes20 through the substrate 29 are precisely machined or formed to provideprecise alignment of the substrate 29 and the device 21 to any alignmentpin or tool pushed through the subassembly's holes. Such an alignmenttool can be the housing of an optical connector 28 that can haveprecisely positioned pins 60 for mating to the other half of itsconnection. The optical connector housing 28 can be machined or formedto accept a heat sink 27 that butts against the back surface of thesubstrate 29 to conduct heat away from the optoelectronic device 21.

FIG. 2 illustrates the substrate 29 with its machined trench 23 and viaholes 20. The trench 23 and the via hole 20 can be machined or formedinto the substrate 29 so that they are in precise alignment with oneanother either through a parallel forming or machining mechanism orthrough a photolithography step that defines both areas at once, or usesprecise mask and mask alignment. Trench 23 has beveled sides 31 allaround to provide for both a guiding feature and to allow anyencapsulant to form correctly.

FIG. 3 illustrates the various embodiments of the trench formed in thesubstrate 29 with alignment holes 41. FIG. 3 a illustrates a rectangulartrench 40 having beveled sides 43 that shows the configuration of thetrench if the substrate would be <100> silicon (or formed by means of amold) and wet anisotropic etching machined the trench. This embodiment40 also illustrates a smaller trench footprint for later illustration.The trench 42 in FIG. 3 b illustrates another trench formed or machinedin the same manner as 40, but allowing for two separate optoelectronicdevice chips to be placed on the substrate along the direction of thewidth of the substrate due to the configuration of trench 42 which isalso formed with beveled sides. Double trenches 44 in FIG. 3 c areformed or machined in the same manner as 40, but allow for two separateoptoelectronic device chips to be placed in a parallel fashion on thesubstrate along the direction of the height of the substrate. Therectangular trench 46 in FIG. 3 d illustrates the machining or formingof a trench in a different manner—if the substrate would be silicon (orformed by means of a silicon mold) and deep reactive ion etching or DRIEmachined the trench (or formed by means of a mold), or if the substratewould be silicon (or formed by means of a mold) and wet anisotropicetching machining the trench which would be a parallelogram. Such atrench does not have beveled sides as shown. The two trenches 48illustrated in FIG. 3 e are formed or machined in the same manner as 46,but allow for two separate optoelectronic device chips to be placed onthe substrate along the direction of the width of the substrate. Notpictured is the option of the embodiment of a trench formed or machinedin the same manner as 46, but allowing for two separate optoelectronicdevice chips to be placed on the substrate along the direction of theheight of the substrate.

The optoelectronic device can be placed within the trench with itsactive area facing out of or into or along the surface plane of thesubstrate.

FIG. 4 illustrates the various embodiments of trenches formed ormachined in the substrate for placement of the optoelectronic deviceinto the back surface of the substrate, where the active area faces intothe substrate and a window is cut out on the front surface for theactive area to show through. Windows are not necessary for wavelengthsfor which the substrate is transparent to the optoelectronic device.Trench 50 in FIG. 4 a illustrates the use of wet anisotropic etching tomachine the resultant front trench if the substrate would be <100>silicon (or formed by means of a <100> silicon mold) and the use of DRIE(or formed by means of the same mold) to form the back trench thataligns and houses the optoelectronic device. The result forms a lip 53which acts as a stop to maintain an optoelectronic device in place andparallel to the disposition of the substrate 29. Trench 52 in FIG. 4 billustrates the use of wet anisotropic etching to machine the resultantfront and back trench if the substrate would be silicon (or formed bymeans of a silicon mold). The result is a beveled front trench 55 and abeveled rear trench 56 which form a lip as shown to provide a guide andstop to hold a component in place. Trench 54 in FIG. 4 c illustrates theuse of DRIE in the back and front of the substrate (or formed using amold for the substrate) to provide both trenches, the front trenchhaving an inner surface 58 and the rear trench having a back surface 57which provide an alignment and stop lip to secure a component in place.Not shown is bonding the active device to the back side without amachining a trench for the device.

FIG. 5 illustrates the various embodiments of the via holes machined orformed into the substrate 29 to provide for alignment to pins oralignment tools. A cut-away side view of a circular hole embodiment ispictured in FIG. 5 b with a top cross-sectional view provided in FIG. 5a. This hole 62 is formed or machined via DRIE or laser drilling. Thehole 62 is viewed face-on in FIG. 5 c with a pin 60 aligned within itsedges. A cut-away side view of a diamond shaped hole embodiment 70 ispictured in FIG. 5 e with a top cross-sectional view provided in FIG. 5d. The hole 70 is viewed face-on in FIG. 5 f with a pin 60 aligned withfour points of contact. The hole can be formed or can be machined viaDRIE or laser drilling or using a wet anisotropic etch if the substratematerial is <100> silicon and the angle of each of the hole's edges is45° off the major flat angle. The square, straight-walled hole can bemachined 45° rotated from what is pictured in 70 if the substrate is<110> silicon. A cut-away side view of a square shaped hole embodiment78 is pictured in FIG. 5 h with a top cross-sectional view provided inFIG. 5 g. The hole 78 is viewed face-on in FIG. 5 i with a pin 60aligned with four points of contact. The hole 78 can be formed or can bemachined using a wet anisotropic etch. The hole 78 can be formed byentirely etching through the front side 74 of the wafer 29, entirelyetching through the back side 76 of the wafer 29, or any combination ofdepths of either. A front cut-away side view of a square shaped holeembodiment 84 with beveled edges 85 in the front is pictured in FIG. 5 kand a back cut-away side view of a square shaped hole embodiment ispictured in FIG. 5 l, with a top cross-sectional view provided in FIG. 5j showing the straight and beveled sides 85. One side of the hole 84 canbe formed or can be machined using a wet anisotropic etch, while theother can be formed or can be machined using DRIE or laser drilling. Asillustrated in FIG. 5 n, a diamond shaped hole 70 can be cut to providetwo points of contact 90 for pin 60 alignment as in the face-on viewFIG. 5 m. As illustrated in FIG. 5 p, a square hole may be cut toprovide three points of contact 92 for pin 60 alignment as shown in theface-on view FIG. 5 o. The multiple points of contact provide alignmentand centering functions and, when mated back together, form four pointsof contact with a circular guide pin 60. As illustrated in FIG. 5 r, acircular hole may be cut to provide an arc of contact 94 for pin 60alignment as shown in FIG. 5 q. Such an arc contact provides for a pressfit of the pin 60 within the hole 62 on substrate 29.

FIG. 6 illustrates an electrically conductive circuit 99 deposited ontoor selectively diffused in the substrate 29 with its trench 23 and holes20. This circuit can provide bond pads 104 for ball wire bonds to theoptoelectronic device and/or its drivers. The circuit fans out at 102 toprovide easier access to the top bond pads 100. The circuit can includeground plane circuits between signal carrying circuits to provide lesscrosstalk between signals.

FIG. 7 illustrates an electrically conductive solder pad 106 to allowfor flip chip or direct bonding of the optoelectronic device and/ordrivers to the substrate 29 with its holes 20 and trench 23. Patternedsolders may be made to reflow to provide for alignment of the devicewith its bottom pads 104 within the trench, or the trench walls used forthe alignment.

FIG. 8 illustrates various embodiments of the substrate providing forperpendicular and backside access to the circuits on or embedded in thefront surface of the substrate 29 with its holes 20 and trench 23. Inthe circuits illustrated in FIG. 8 a, the edge conductors 110 are formedby anisotropic etching of silicon or forming of some other material intothe v-shaped trough 114 and depositing an electrical conductor on ordiffusing a conductive layer into the surface. The substrate can then becut to form two pieces as in FIG. 8 c, one of which becomes the chipshown in side cross-sectional view in FIG. 8 d with a sloped trough forreceiving the array circuit. The edge connection 110 providesperpendicular access to the optoelectronic device's circuits. In thecircuits illustrated in FIG. 8 e, the edge conductors 120 are formed byanisotropic etching of silicon or DRIE or laser drilling of thesubstrate material or forming of some other material into therectangular trough shape 122 and depositing an electrical conductor onor diffusing a conductive layer into the surface. The substrate can thenbe cut to form two pieces as is shown in FIG. 8 g, one of which becomesthe chip as is shown in side cross-sectional view in FIG. 8 h as anotched trough. The edge connection 120 provides perpendicular access tothe optoelectronic device's circuits. In the circuits illustrated inFIG. 8 i, the edge metallizations 128 are formed by DRIE through thesubstrate material or forming of some other material into the shape 130and depositing an electrical conductor on into the surface. Thesubstrate is then cut to form two pieces as is shown in FIG. 8 k, one ofwhich becomes the chip as is shown in side cross-sectional view in FIG.8 l with its concave troughs for termination of the array circuit. Theedge connection 128 provides perpendicular and backside access to theoptoelectronic device's circuits.

FIG. 9 illustrates the alignment and bonding of the optoelectronicdevice 21 into the alignment trench 23 of substrate 29. The shape of thetrench, with its beveled sides, receives the device and aligns it at thesame time, eliminating the need for further alignment. Ball wire bonds30 affix the electrical connections on the front face of the device 21to the bond pads in or on the substrate's surface.

FIG. 10 illustrates the use of “flex” circuitry ISO connected to theedge circuit of the array to carry the electrical signals away from thesubstrate in a protective flexible conductor. The flex circuitry may beconnected to the top edge circuit by any of the means heretoforedescribed.

FIG. 11 illustrates the use of via holes 155 to carry the electricalconnections for the optoelectronic device to the back surface of thesubstrate 29 with its rectangular trench 40. FIG. 11 a illustrates acut-away side view, while FIG. 11 b illustrates a cross-sectional sideview. Various embodiments of the via holes with conductive layers areshown in FIGS. 11 c-e. The embodiment of a straight hole 156 shown inFIG. 11 c can be formed or can be machined by DRIE or laser drilling.The embodiment shown in FIG. 11 d with its hourglass shaped hole 157 canbe formed or can be machined by a combination of wet anisotropic etchesinto silicon, one on the back surface and one on the front surface. Theembodiment shown in FIG. 11 e with its tapered hole 158 can be formed orbe machined by wet anisotropic etch on one surface of a <100> siliconsubstrate. It should be noted that such deep holes could be made tohouse optical fibers perpendicular to the surface and that such holescould be made in an array for an opposing chip which would be used toform an independent fiber to fiber or fiber to device connection system.

FIG. 12 illustrates the injection of a known precise quantity ofencapsulant 162 to fill flush to the surface of the alignment trench 23.In FIG. 12 a, a cut-away side view of the substrate with circuit traces,solder, optoelectronic device, and encapsulant 162 is shown. The sidecross-sectional view FIG. 12 b illustrates the flat surface achieved bymolding the encapsulant 162 flush to the surface of the substrate andcuring it.

FIG. 13 illustrates the method by which an optoelectronic device isfitted into the substrate 29 through the back surface trench as definedin 50, FIG. 4 a. The device 21 is fitted face-first into the backsurface trench of 50 as in the top cross-sectional view FIG. 13 b. InFIG. 13 c, the back surface face-on view illustrates the conductivecircuit traces and solder bond pads 24 for the device 21. In FIG. 13 d,the back surface face-on view illustrates the device 21 in place withits back facing out and its active area facing into the substrate. Thelip 163 formed by the intersection of bevel 164 and straight side 165holds device 21 in place in an aligned position.

FIG. 14 illustrates embodiments of the molded encapsulant face toinclude, but not to limited to, optical elements like lenses and mirrorson a substrate 29. In FIG. 14 a, a lens 180, made of a roundedprotrusion, spreads the light L coming out of the optoelectronic device21 if 21 is a light emitting device, or 180 focuses the light L cominginto the device 21 if 21 is a light receiving device. In FIG.1 4b, thedevice 186 is a light emitting device like a VCSEL, LED, or SLED, whilethe device 188 is a light receiving device like a PIN diode. A portionof the light transmitted from 186 reflects off of angular surface 182into the active area 188, where it is detected. This configuration isuseful for monitoring the power of 186. The angle of surface 182 can becalculated to provide for the correct amount of reflected light toimpinge upon 188.

FIG. 15 illustrates the fashioning of an optical connector housing 28that has the same spacing and alignment as a mating connector withfibers or waveguides embedded in it. The optical connector housing 28has alignment pins 60. It also has a feature such as slot 91 thataccepts a protrusion 92 on heat sink 27 into its body so that theoptoelectronic device on the substrate 29 can thermally conduct throughit. In FIG. 15 a, the connector housing 28 and the heat sink 27 aredisplayed separately. In FIG. 15 b, the heat sink and the housing havebeen assembled, and the optoelectronic coupler subassembly 195 isdisplayed separately. In FIG. 15 c, all the parts have been assembled.The subassembly 195 and the heat sink 27 would be affixed to theconnector housing 28, but the pins 60 could be removed once the assembly195 is bonded in place. The device is ready for connection via solderbumps 25 to an array, a circuit, drivers or the like.

FIG. 16 illustrates, in FIGS. 16 a, 16 b and 16 c the sequence ofcoupling of a fiber optic array connector 210 to the optoelectronicsubassembly 205. The guidepins 60 used to align substrate 29 andcomponent 28 have been removed as the two pieces were bonded. The fiberoptic array connector 210 with its flex cord 211 has pins 160 which inturn are inserted into holes 20 of substrate 29 which previouslyreceived pins 60 for alignment purposes prior to bonding. Once 210 isinserted into holes 20 the device can be considered complete or it isfurther bonded together.

The invention herein allows for a large degree of wafer integration. Itallows for the use of etching to provide for passive alignment ofcomponents within an assembly of components. A large plus to thisinvention is the utilization of existing components, such as those shownin FIGS. 15 and 16 as 28 and 210 respectively, in the subassembly. Thisnegates the need for expensive manufacture of all new components toachieve this positive passive alignment while at the same time providinga superior platform for the technology. The invention allows for directbonding of the device to the carrier or other component and for solderor patterned metallizations in the recesses. This allows for flip-chipbonding of pads on the active device to the carrier.

It also allows for possible ground plane metals extending between thetraces to help prevent crosstalk in the final module. It also allows forconnection to flex (metal conductors in/on a flexible medium) at adistance where there is no interference from the other connector orfunctions on the face.

The ability to accurately construct the trenches also allows fordisposition of a known amount of transparent (can be non-transparent ifother optical paths are chosen) encapsulant can be injected to formoptical surface. It also allows for the insertion of a filter or otheroptical elements. This can incorporate coatings to change thereflectivity and transmission such as bandwidth, etc. The use ofencapsulant protects against damage due to abrasion, water, and dust tothe wire bonds. It is possible to emboss or otherwise shape theencapsulant to form a singular or array of small lenses to optimallycouple the light in and out of the system. These can deflect the lightto photodiodes to monitor the output of the light. Transparent slidescan be inserted into the encapsulant to alter the light transmissionqualities thereof.

The silicon wafers can be etched using wet or dry processes. Theapertures can be metallized to pass signals from one side of the carrierto the other side. The use of CVD metal deposition and physical vapordeposition at a tilted or variable incident angle is also contemplated.Holes can be etched though the wafers or substrates using isotropic oranisotropic etching giving perpendicular access allowing subsequentmetallization of the trenches. The trenches can be filled with solderfor connection to another substrate or board and can have pass throughconnections as described herein from both the edge perpendicular and theopposite side. I.e, the holes can be etched so as to pass electricalconnections up to the top edge of the substrate as well as to theopposite side. The etching provides for passive alignment features bothin the trench and the holes. A heat sink can be attached to thecomponent with the active portion extending away from the heatgenerating device which enhances the operation of the sink.

The use of the guide pins and alignment system allows the component toserve as a one time alignment guide to fiber array ferrules whichutilizes the mechanics of the fiber array for subsequent matings. Thesystem also allows for board to board free space optical connection.Components having integrated ICs can be connected up as well.

An important consideration is that many of the steps in providing thecomponents are integrated at the wafer level which allows for huge costsavings to be made. This allows also for greater thickness in faceplates and requiring only minor changes to be made to the housings whichconnect and aligns the two ferrules.

Where the operation of devices is 1200 to 1600 nm, the carrier(substrate) is transparent the devices may be mounted facing the carrierin a etched recess. If the carrier is not transparent the cut-outsection may be etched so as to be in communication with the trench. Insuch a case a non-transparent encapsulant may be utilized.

Having shown and described the invention in its many incarnations itwill be obvious to those of ordinary skill in the art that many changesand modifications can be made without departing from the scope of theappended claims

1. An optoelectronic component, comprising: a silicon substrate; anoptoelectronic device mounted on the silicon substrate; an encapsulantover the optoelectronic component; and a flexible circuit attached tothe silicon substrate and electrically connected to the optoelectronicdevice.
 2. The optoelectronic component of claim 1, wherein the siliconsubstrate has a trench in a first surface thereof and the optoelectronicdevice is disposed in the trench.
 3. The optoelectronic component ofclaim 1, wherein the flexible circuit is attached to the siliconsubstrate along an edge of the substrate.
 4. The optoelectroniccomponent of claim 1, wherein the silicon substrate has a via holetherethrough.
 5. The optoelectronic component of claim 1, comprising aplurality of the optoelectronic devices.
 6. An optoelectronic component,comprising: a silicon substrate having a micromachined feature; anoptoelectronic device mounted on the silicon substrate; and a flexiblecircuit attached to the silicon substrate and electrically connected tothe optoelectronic device.
 7. The optoelectronic component of claim 6,wherein the micromachined feature is a via hole through the siliconsubstrate.
 8. The optoelectronic component of claim 7, wherein thesilicon substrate has a trench in a first surface thereof and theoptoelectronic device is disposed in the trench.
 9. The optoelectroniccomponent of claim 7, wherein the flexible circuit is attached to thesilicon substrate along an edge of the substrate.
 10. The optoelectroniccomponent of claim 6, wherein the micromachined feature is a trenchformed in a first surface of the silicon substrate, and theoptoelectronic device is disposed in the trench.
 11. The optoelectroniccomponent of claim 10, wherein the flexible circuit is attached to thesilicon substrate along an edge of the substrate.
 12. The optoelectroniccomponent of claim 6, comprising a plurality of the optoelectronicdevices.
 13. An optoelectronic component, comprising: a siliconsubstrate; a plurality of optoelectronic devices mounted on the siliconsubstrate; and a flexible circuit attached to the silicon substrate andelectrically connected to the optoelectronic devices.
 14. Theoptoelectronic component of claim 13, wherein the silicon substrate hasa trench in a first surface thereof and the optoelectronic devices aredisposed in the trench.
 15. The optoelectronic component of claim 13,wherein the flexible circuit is attached to the silicon substrate alongan edge of the substrate.
 16. The optoelectronic component of claim 13,wherein the silicon substrate has a via hole therethrough.